1. Field of the Invention
This invention relates generally to improvements in control processes used in active control applications, and active control of sound or vibration. More particularly, this invention reduces the computations associated with the adaptation process used to tune a controller to accommodate system variations by using a more efficient algorithm to implement sound and vibration control logic.
2. Background Art
Conventional active control systems consist of a number of sensors that measure the ambient variables of interest (e.g. sound or vibration), a number of actuators capable of generating an effect on these variables (e.g. by producing sound or vibration), and a computer which processes the information received from the sensors and sends commands to the actuators so as to reduce the amplitude of the sensor signals. The control algorithm is the scheme by which the decisions are made as to what commands to the actuators are appropriate. The amount of computations required for the control algorithm is typically proportional to the frequency of the noise or vibration.
Many active noise or vibration control problems, particularly those involving high frequency disturbances, have significant changes in the transfer function between actuator commands and sensor response over the system operating regime. Adaptation to these changes is required to maintain acceptable performance. The computational requirements associated with the adaptation process can be unduly burdensome. Therefore, what is needed is a system that reduces computational requirements to implement an adaptation process sufficiently rapidly to maintain performance in the presence of a rapidly time-varying system.